Pneumatic suspension fed by compressed air



Patented Nevers, 1927.

' UNITED STATES misses PATENT orricr..

HENRI MERCIER, OF PARIS, FRANCE.

PNEUMATIC SUSPENSION FED BY COMPRESSED AIR.

Application filed April 3, 1922, Serial No. 549,179, and in France April 5,l 1921.

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high pressures resulting in a corresponding decrease in volume. The elimination of oil leakage loss also increases the cleanliness of the installation as a whole. l

The main features of the invention are as follows:

1. .The use of a return system whereby the compressed air with its entrained oil is returned to a closed reservoir which in turn supplies the compressor, thus providing for a minimum use of additional air.

2. The use of a suction system for maintaining a decreased pressure in the lubrication areas and the stuiing boxes, so that oil leakage is collected and subsequently returned to the system by the compressor.

Other objects and 'features will be apparent'from the following description and the accompanying figures. The inyentionisnotlimited to pneumatic suspensionsoperated by compressed air, butmay be applied to any type of apparatus functioning in a similar manner, such as, for example, vehicle brakes.

In the accompanying drawings:

Figure 1 shows tion applied to pneumatic suspensions fed continuously.

Figure 2 shows a modiied'construction when the pneumatic suspensions are not fed continuously.

Figures 3 and 4 show stulling rings particularly Well adapted for use in said sus# pensions.

In these figures, the aXle is shown at 1, the' movablefpart of the suspension connected to the axlevat 2, the fixed part of said suspension fixed to the chassis is at 3,

the packing, preferably, a cup leather as shown in Figures 3 and 4 is indicated at 4,

and the compressor 5 which is worked either by the motor of the vehicle or by any other means. vThe members 2 and 3s communicate 55"with each other through the tube 4;a for the an example of the inven-4 In Figure 1, 6 is a special distributing valve working synchronously with the com` pressor and at a speed whereby for each stroke of the piston the compressed air may be in tirn directed through the port 6 to the four pipes 7, 8, 9 and 10 leading to the four suspension apparatuses of the vehicle, assuming of course that four are provided. The regulating leak is indicated at 11. The compressed air which escapes from said leak, passes through va conduit 12,.l into a reservoir 13 to which are also connected the pipes 14, 15 and 16 leading from the three other Suspensions of the vehicle, not shown. Four valves 17, 18, 19 and 20 are placed on the fittings of the pipes 12, 14, 15 and 16 connected to the reservoir 13. This reservoir carries a valve 21 which opens to theatmospliere, a spring beingprovided to allow the opening of the valve only when the pressure in the reservoir 13 reaches a certain value. The reservoir 13 is connected to the compressor by a conduit 22 and said compressor is connected to the valve 6 by a delivery pipe 23.

The compressor has two suction valves 24 and 25 .and a delivery valve 26 arid two crank case valves, a suction valve 27 and a delivery valve 28. The suspension devices are provided with annular grooves such as shown at 29, and are connected with the atmosphere by a helical conduit such as 30, and with the crank case of the compressor by the pipes 31, 32, 33, 34 and 35.

Finally, the oil and air driven vfrom the crank case through the pipe 36 is delivered above the tubing 37 through which atmospheric air is sucked by the compressor.

In the modilied form shown on Figure 2,l

only one suspension apparatus has been shown, as in Figure 1, the compressor and reservoirs are the same for all the suspensions of the vehicle. 38 is the annular groove of the member 3 on the down stream side of the packing 4 of the suspension. 39 is the helicoidal groove which connects said groove 38 with the atmosphere, this connection being vsomewhat restricted. 40 is the suction conduit which connects the groove 38 with the compressor.

The compressor is provided with an automatic suction valve 41, a delivery'valve 42 and a suction valve 43 fitted with a spring of suliicient resistance to allow ,its opening only through the action of a tumbler 44 ushed by a rod 45, which is itself moved y a suitable cam fixed on the shaft of the compressor.

The axis of said tumbler 44 is placed on a lever 46, which can rotate on an axis 47. This lever is acted upon by a piston 48 and a spring 49 which brings it back automatically in the position shewn on the gure. The piston 48, through conduit 50, is under the action of the pressure existing .in the delivery conduit 51 of the compressor or of the reservoir 52 The compressor in addition, is provided with an opening or inlet 53 exposed at the end of the stroke, which is connected by a' conduit 54 with a reservoir 55, this latter being provided with a valve 56 through which the reservoir communicates with the atmosphere, said valve having a spring which y permlts opening only when the pressure in the reservoir 55 reaches a certain value. 57 is the valve or distributor of the device of the suspension, it has the shape of a piston valve, the rod having a terminal roller 59, and being maintained in contact with the cam 60, by compressed air thru pipe 62, which leads from reservoir 52; and said cam 60 is connected either to the axle of thevehicle or to the suspension itself. rlhe number of valves is equal to the number of suspensions on the vehicle.

u Each valve .is connected with the suspension apparatus by a conduit such as61 which is used either for admission or exhaust (regulating leak) of the compressed air mixed with oil of the suspension, according to the position of the piston valve 58 whichy acts in accordance with the requirements Xof the suspension. This last is connected to the reservoir 52, through conduit 62 for admission,

or connected by conduit 63, with reservoir 55,

for exhaust.

On Figures 3 and 4 are shown stuiiin or packing rings which are particularly e ective for use in the suspension apparatus, in which ,the packing rings must -be absolutely tight without increasing the friction Figure 3 shows an improved packing which Ais absolutely tight without undue friction in fact with less friction than the ordinary cup made of leather or any other materiah On the figure the cup leather is shown at 64, and is surrounded by a certain number of split segments which can expand such as 65, 66, 67, the slits 68, .69, of these segments being displaced s'o that they do not register under the pressure of the cup leather, the slitsl are left somewhat large. Thesegments 65, 66, 67 rub only on the cyl- Figure 4 shows aimodified form of the packing ring of Figure 3, the cup leather being replaced by a segment 71, bearing on and conduit 23 to the distributor 6 which 4 admits then air, in turn, to the four suspension apparatuses through conduits 7, 8, 9

and 10. The pressure increasing these lift the vehicle, and take the position shownon Figure 1,

the pressure in each apparatus corresponding to the load thatthey have to bear.

From this moment, the compressed air and oil which is supplied to the suspension apparatus leaks through the openings 11 through the pipes 12, 14, 15 and 16 and check valves 17, 18, 19 and 20 into the'reservoir 13, the pressure in said reservoir not being able to increase beyond a certain limit on account of the valve 21.

But as the compressor is still running it does not draw any atmospheric air through valve 25, suction taking place preferablyr through valve 24 connected to the reservoir 13, the check valve 13 opening before check valve 25 on account of the greater pressure existing in said reservoir. It follows that'a regular continuous circulation of compressed airmixed with oil, without any expansion except the one due to the loss of head in the conduits, is established, the compressor acting only to move the iiuids once the proper pressure is reached. During the timeithat the compressor is working a continuous suction takes place in the crank-case through the conduits 35, the conduits 31, 32, 33,34 and grooves 29 of the suspension apparatus,

the small quantity of air entering through the grooves carrying with it the oilfrom the 4packngs into the crank-case of'the'compres-` sor, where it is used for lubrication, the excess going through conduit 36, to the pipe 37 and then in the chamber of valve 25 from.

which it is sucked with the first suction of atmospheric air.

The working of the device shown in Figp groove. When the piston has travelled thenecessary distance, about one-fifth of .its stroke the valve 43 is raised on account of the action of tumbler 44 and rod 45 moved by a cam of the compressor. The piston then sucks atmospheric air, the valve 43, under 40. der orv isadded to atmospheric air which has the action of the tumbler 44 closing before -already been sucked through 41 and 43, the the opening of the inlet 53 by the piston. whole of this gas is then pushed'througb In coming back the piston pushes the air valve 42 into reservoir 52 from which it is sucked from reservoir 55, through valve 42, used to supply the suspension apparatus.

5 conduit 51, into the suspension apparatus, The decrease of pressure in the groove 38 through conduits 62 and 61, the piston valve or 39 may be obtalned by any other means 58 of distributor 57 being then in the right such as an independent pump for example, position to permit the flow of air. When worked by the motor or the axle or even the the pressure has the required value, the sussuspension itself.

10 pension Works lifting the vehicle, the cam l claim- 60 in its motion moving the piston va'lve 58, 1. A pneumatic suspension apparatus for and closing the connection between conduit road vehicles comprising aco-operating pres- 62 and 61. The pressure now increases in sure cylinder and load supporting piston the reservoir 52 up to the point Where the adapted to be operatively connected to the 1;, compressed air acts on piston 48 through by chassis and axle of said vehicle, an air compass 50, against the action oi' the spring 49. pressoiadapted to supply air under pressure Lever 46 turns around 47 and pushes back to said pressure cylinder, means adapted to the tumbler 44 of valve 43 and acting rod yreturn a portion of the air supplied to said i 45. Valve'43, kept on its seat byv its spring, pressure cylinder to said air compressor, and 2o cannot act, and it follows that the coma valve in said means positively operated by pressor ceases to accumulate air in the reserthe 'linear relation of said piston and .said voir 52, the small quantity of air passing pressure cylinder for controlling the last through the valve 41 being negligible. mentioned means.

When on account of movement of the sus- 2. A pneumatic suspension apparatus for g5 pension the piston valve 58 is moved by the road vehicles, comprising a co-operating cam 6() which permits connection between pressure cylinder and load supportin piston conduits 61 and 63, the compressed air of the adapted to be operatively 'connecte to the suspension escapes through 61 and 63 and chassis and axle of said vehicle, a chamber the pressure in the reservoir 55 increases. interposed betweenthe cooperating Walls of 3o If said pressure goes beyond the limit assaid piston and cylinder, a helica'l conduit signed to valve 56, escape takes place into the formed between the walls and communicating atmosphere. with said chamber, at one end and the at- But whether valve 56 is open or closed the mosphere at the other, an air compressor compressor still runs, air under pressure and having intake and supply ports, means con- 35 not expanded (or hardly expanded) comnecting said chamber with the intake of said ing from the suspension a paratus into compressor, and means connecting the supreservoir 55,'passing throug conduit 54, ply port of said compressor with the preswhen the piston in its reciprocatinghmotion sure cylinder, substantially as described. uncovers opening 53 and a1r llingt e cylin In testimony-whereof I aix my signature.

HENRI MERCIER. 

